Charles Web Debugging Proxy or Charles for short is a commercial and multi-platform application that provides web developers with an easy way to monitor and debug the HTTP and HTTPS traffic between their web browser and the Internet.

With this software you will be able to save a lot of time, as it helps you to quickly discover and eliminate bugs that may occur during the actual communication between your web browser and the Internet.

Features at a glance

Its key highlights include support for HTTP over SSL (HTTPS) connections, download statistics, simulation of slower Internet connections, as well as the ability to record and store all the traffic between the Internet and their computer, such as cookies, requests, headers, responses, and caching information.

Even though the Firefox add-on is offered as an optional download on the project’s homepage, the application will ask users to install it when running Charles for the first time, as it is used to configure the software as a proxy for the web browser.

It features support for Unicode character encoding, NTLM authentication, HTTP 1.1 protocol, external proxy, AMF parsing, session recording, website blacklist, keyword search of all bodies and headers, as well as reading of HTML, XML, JavaScript, and CSS files.

Under the hood, supported OSes and pricing

The application is written in the Java programming language and it’s compatible with the Linux, Microsoft Windows and Mac OS X operating systems. It is distributed as binary files for each supported platform, as well as a universal add-on for the Mozilla Firefox web browser.

While Charles is especially useful for Flash developers, it can also be used for XML development in web browsers, such as AJAX and XMLHTTP. It is free only for 30 days, after that you will need to pay $50 (36 EUR) for a single license. However, it’s cheaper with 40% if buying over 10 licenses!

Charles Web Debugging Proxy was reviewed by Marius Nestor, last updated on November 16th, 2014